A Graphene Reinforced Fabric Phase Sorptive Extraction Method for Determination of Ochratoxin A in Food Samples

In the present study, a novel sorbent-based microextraction method was developed for the quick extraction of ochratoxin A from food samples. The extraction was performed based on graphene-reinforced fabric phase sorptive extraction (FPSE) followed by HPLC-FLD analysis. Chromatographic separations were performed on a C18 column with H2O: ACN: acetic acid (49:49:2, v/v/v) as mobile phase at a flow rate of 1.0 mL/min and with fluorescence detection (λex= 333 nm and λem= 447 nm). The effect of graphene in the sol solution, extraction time, ionic strength, solvent extraction volume, desorption time, and desorption solvent type and volume were evaluated to obtain the maximum extraction efficiency. The optimum condition was obtained at pH=7, 40 mg of graphene per 10 mL of sol solution, 40 min for extraction time and 20 min for desorption time, the best solvent for desorption was 1 mL of ACN: HOAC (95:5 V/V) and extraction volume was 10 mL. The method showed a linear range of 2.0-17.5 ng/mL with a correlation coefficient greater than 0.97. The limit of detection and limit of quantification were found 0.49 ng/g and 1.49 ng/g, respectively with absolute good recoveries (67.7-104.0%) and low relative standard deviations. In addition, ochratoxin A was quantified with the developed method in wheat and chickpea samples and the results indicate the effectiveness of the presented method.